OTTAWA - After splashing out over $20 billion for the military in its last two federal budgets, the Conservative government is tightening the purse strings.

The Defence Department came away from Tuesday's federal budget with no new money for big-ticket items, a relatively small increase in operational spending, and the promise of a slightly bigger increase down the road.

The fiscal plan makes no mention of capital purchases despite a list of equipment needs, including the urgent replacement of the country's aging fleet of search-and-rescue planes.

The budget promises to increase defence spending over the next three years by 1.5 per cent and guarantees annual increases of two per cent after 2011 -- the year Canada is expected to withdraw its combat troops from Afghanistan's volatile Kandahar region.

The commitment, which will bring the overall defence budget to over $18 billion, is in line with a promise made last week by Prime Minister Stephen Harper.

But critics, such as Liberal Senator Colin Kenny, have argued the budget needs to be set much higher in order to make up for years of neglect.

In the previous two budgets, the Conservatives set aside over $20 billion for military hardware purchases, including new transport aircraft, tanks and upgrades on the country's frigates.

The absence of new capital projects in the current budget raises questions about several key programs, including the replacement of the navy's aging destroyers and the air force's geriatric Buffalo search planes on the West Coast.

However, Finance Minister Jim Flaherty said the government remains committed to defence.

"Our government is also delivering additional support for our brave men and women in the Canadian Forces and their families,'' he said in his budget speech.

"In this budget, we are providing stable, predictable funding with annual increase in defence spending of two per cent starting in 2011-12.''

In the current budget year, reconstruction efforts in Afghanistan will see a boost of $100 million. That brings Canada's total aid and rebuilding contribution to the war-torn country to $1.3 billion over 10 years -- a pot of money administered by the Canadian International Development agency.

The Conservatives have faced repeated criticism in the House of Commons that military spending dwarfs what the country sets aside for aid and reconstruction.

Last fall, defence bureaucrats were warned by the Privy Council Office to closely mind their budget in the coming year and not to expect any top-ups. Since Canadian troops deployed to Kandahar in February 2006, operational costs have routinely exceeded estimates, requiring special appropriations.

The Conservatives promised in the last election campaign to increase the size of the military -- both regular and reserve. But figures released last fall show they did not put enough money into their first budget in 2006 to meet their commitments -- forcing the government to scale back the size of the expansion.